We propose to examine the biochemistry and immunology of 2', 3'-cyclic nucleotide 3'-phosphodiesterase from mammalian subcortical white matter. We propose to determine the CNS localization of the enzyme at the electron microscope level and to examine the immunological relationshops among the CNS, PNS, and extraneural enzyme(s) using the monospecific antibodies previously raised against the purified human and bovine enzymes in New Zealand White rabbits.